Biomedical subjects

Pablo Engel

Publications and source records attributed to Pablo Engel.

22 records · Page 2Linked to original sources

PubMed2002

Mouse novel Ly9: a new member of the expanding CD150 (SLAM) family of leukocyte cell-surface receptors.

Human CS1, also known as novel Ly9, 19A24, or CRACC, is a member of the immunoglobulin gene superfamily (IgSF) expressed on natural killer cells and other leukocytes. Here we describe the cloning of the mouse homologue of this gene. The mouse novel Ly9 gene is shown to encode a transmembrane protein composed of two extracellular immunoglobulin-like domains, a transmembrane region and an 88-amino acid cytoplasmic domain. Mouse novel Ly9 is structurally similar to the extracellular domains of CD84 and CD229 (Ly9). Both mouse and human novel Ly9 genes mapped close to the CD229gene in a region where other members of the CD150 family have also been mapped, and analysis of their genomic sequences showed that they have an identical intron/exon organization. Northern blot analysis revealed that the expression of mouse and human novel Ly9 was predominantly restricted to hematopoietic tissues, with the exception of testis. Here we show that SAP (SH2D1A), an adapter protein responsible for the X-linked lymphoproliferative disease, binds to the phosphorylated cytoplasmic tail of human but not mouse novel Ly9. Taken together, these data indicate that mouse novel Ly9 is a new member of the expanding CD150 family of cell surface receptors.

Amino Acid Sequence↗

PubMed2002

Shedding of TNF-alpha receptors, blood pressure, and insulin sensitivity in type 2 diabetes mellitus.

Tumor necrosis factor-alpha (TNF-alpha) is increasingly recognized as a key component in the development of insulin resistance and increased blood pressure. In a sample of 368 individuals, the ratio of soluble TNF-alpha receptors (sTNFR2/sTNFR1) correlated positively with systolic and diastolic blood pressure (P < 0.01). This ratio was significantly greater in type 2 diabetic subjects (DM-2) than in type 1 diabetic patients and was greater than in control nondiabetic subjects (P < 0.00001). The TNF-alpha receptor 1 (TNFR1) density in peripheral blood monocytes was similar in DM-2 patients and in nondiabetic subjects. After phorbol 12-myristate 13-acetate, TNFR1 shedding was significantly decreased in DM-2 compared with control subjects, and it was directly associated with insulin sensitivity (r = 0.54, P = 0.03). Serum sTNFR1 concentration was also linked to the vasodilatory response to glyceryltrinitrate (P = 0.01). Conversely, TNF-alpha receptor 2 shedding was negatively associated with insulin sensitivity (r = -0.54, P = 0.03), whereas shedding of L-selectin showed no significant association. After exercise-induced lowering of blood pressure, a parallel decrease in sTNFR2/sTNFR1 was observed in DM-2 patients. Our findings suggest that insulin resistance and blood pressure are linked to altered shedding of TNF-alpha receptors in DM-2. The latter seems reversible and is not genetically determined.

Adult↗

PubMed2002

The role of P-selectin in experimental colitis as determined by antibody immunoblockade and genetically deficient mice.

We assessed the effects of genetic ablation of the P-selectin gene in comparison with functional immunoblockade of P-selectin on leukocyte recruitment and the course of disease in dextran sulfate sodium-induced colitis in mice. Compared with control antibody-treated wild-type (WT) mice, WT mice treated with anti-P-selectin antibody and P-selectin(-/-) mice had significantly decreased leukocyte rolling and adhesion in colonic venules and reduced clinical and pathological colitis scores. These reductions were more pronounced in anti-P-selectin-treated than in P-selectin(-/-) mice. In colonic endothelium, up-regulation of ICAM-1 was similar in WT and P-selectin(-/-) mice, but VCAM-1 up-regulation was significantly higher in the latter group. Lung leukocyte infiltration and VCAM-1 expression were increased only in P-selectin(-/-) colitic mice. Mortality was observed only in P-selectin(-/-) mice. Therefore, ablation of P-selectin function ameliorates colitis, but this protection is attenuated in P-selectin(-/-) mice, probably due to compensatory mechanisms that involve up-regulation of other adhesion molecules such as VCAM-1.

Animals↗

PubMed2002

Concanavalin-A-induced liver injury is severely impaired in mice deficient in P-selectin.

P-selectin (CD62P) is an adhesion molecule that mediates the initial attachment of leukocytes to activated platelets and endothelial cells in damaged tissues. We evaluated the role of P-selectin in concanavalin A (Con A)-induced hepatitis, a model characterized by CD4(+) T cell activation and infiltration of the liver. Con A injection induced transient P-selectin expression on hepatic venules and platelets. Mice lacking P-selectin showed impaired lymphocyte adhesion to liver venules and sinusoids, a striking reduction in intrasinusoidal occlusion, and decreased lymphocyte infiltration of liver parenchyma. The reduction in transaminase levels and the almost complete abolition of necrotic injury demonstrated that liver damage was lower in P-selectin-deficient mice. In wild-type mice, pretreatment with the P-selectin-blocking monoclonal antibody attenuated the sinusoidal occlusion and reduced the rise in transaminases after Con A treatment. These results implicate P-selectin in the development of Con A-induced liver injury and reveal the protective effect of blocking P-selectin in this hepatitis.

Alanine Transaminase↗